Pomponius, On Sabinus, Book XI. Where a person who received a loan has judgment rendered against him in an action on loan, on the ground that the property had disappeared; security must be furnished him that if the owner finds it, he will deliver it to him. 1Where a party receives something for the purpose of trying it, as, for instance, beasts of burden, and they are hired out by him, and he profits by this use; he must refund the actual amount which he obtained to him who let him have the animals on trial; for no one should be allowed to profit by anything before it is held at his risk. 2Where I lend an article to a free man who has been serving me in good faith as a slave, let us see whether I am entitled to an action on loan against him. Celsus, the son, says that if I had ordered him to do anything, I could proceed against him either by an action on mandate, or by an action for the construction of the contract, and therefore the same rule should apply in the case of a loan. It makes no difference whether, if we contract with a freeman who is serving us in good faith as a slave, we do not do so intending to place him under an obligation, for it frequently happens that a tacit obligation arises in addition to what is intended at the time; as, for instance, where money which is not due is paid by mistake for the purpose of discharging a debt.

Pomponius, On Sabinus, Book XI. We adopt the rule that where exceptions are interposed against the purchaser, and they prevail, the vendor will not be liable; but where they have reference to the act of the vendor, the contrary rule applies. For it is certain that the purchaser will have no right to an action either on purchase, or under the stipulation for double, or even simple damages, where an exception based on his own act is successfully pleaded.

Pomponius, On Sabinus, Book XI. If you should sell me property belonging to another, and I should repurchase it from the true owner; Celsus, the son, says that the opinion of Nerva is not correct; namely, that you, in bringing an action on sale, can recover the price from me; because I was, as it were, entitled to the property, since it is not agreeable to good faith that I should hold property under a title belonging to someone else. 1Where a stipulator for double damages instead of being the possessor becomes the claimant and loses his case, if he had been in possession of the property he could have retained it, but he cannot legally bring suit to recover it, as the promisor of double damages will be secure by operation of law, or he can undoubtedly protect himself by an exception on the ground of fraud. This, however, is the case only where possession was lost through the negligence, or with the consent of the stipulator for double damages. 2The vendor can be notified to appear at any time whatsoever when the matter is brought up in court, because a certain date is not fixed by this stipulation; provided, however, this is not done before the time that judgment is rendered.

Pomponius, On Sabinus, Book XI. If my slave is serving you in good faith, and he purchases something which is delivered to him, Proculus says that it will not become mine, because I have not the slave in my possession; nor will it be yours, because it was not acquired by means of your property. If, however, a freeman buys anything while he is serving you as a slave, it will belong to him individually. 1If you are in possession of property belonging to me, and I wish it to be yours, it will become yours, even though it may not have come into my hands.

Pomponius, On Sabinus, Book XI. Real is better than personal security.